Good afternoon Mojang!
I have been playing Minecraft Bedrock for a long time, and for at least several months I face a very annoying bug that prevents light from proper working. Some chunks just keep being dark even after I place sources of light. If I build a vertical structure, this bug stops from appearing, but I cannot cover all free space on the map with structures. I attached some screenshots so you can observe the issue yourself.
Thank you for your report!
We're actually already tracking this issue at MCPE-58182, so I will resolve and link this ticket as a duplicate.
If you would like to add a vote and any extra information to the main ticket it would be appreciated.
If you haven't already, you might like to make use of the search feature to see if the issue has already been mentioned.
Quick Links:
📓 Issue Guidelines – 💬 Community Support – 📧 Customer Support – 📖 Game Wiki